The invention pertains to a self-drilling blind tension rivet which includes a rivet casing with a stop flange and a rivet spindle on one end of which a drilling unit is provided, and at other end region of which at least one rotation and tension force application element is provided to apply force by rotation and tensioning of a tool for drilling and setting the blind tension rivet.
Self-drilling blind rivets have already become known in various designs. For example, a self-drilling blind rivet is known from DE-A-2,554,557, where the rivet spindle or shank has over its entire length two parallel surfaces that extend along the spindle where the rivet casings or sleeves have surfaces complimentary to the surface of the spindle, in order to achieve a torsion-locked connection between the rivet spindle and the rivet casing. On the one hand, a special construction of the rivet casing is recruited, whereby the rivet spindle and the rivet casing must be precisely tailored to fit each other. On the other hand, immediately upon setting of the rivet, that is, upon application of tensioning movements, problems arise. When setting a tightened blind rivet relatively large forces, acting in the axial direction of the tensioning spindle, must be applied, so that a fixed clamping of the rivet spindle in an appropriate tool is necessary.
The same problems arise in a design of a self-drilling rivet disclosed in DE-A-2,548,860 where the rivet spindle has a quadratic cross-section. In this design as well, it is intended that a rotation-locked connection be established between the rivet spindle and the rivet casing, and thus here too, a special design of the open area cross section of the rivet casing will be needed.